Viral infections are a significant medical problem. For example, herpes is a widespread human pathogen, with more than 90% of adults having been infected. Due to latency, once infected, a host carries the herpes virus indefinitely, even when not expressing symptoms. Similarly, human papillomavirus, or HPV is a common virus in the human population, where more than 75% of people will be infected. A particular problem is that viral infections may lead to cancer. For example, integration of HPV into host DNA is known to result in cancer, specifically cervical cancer. The Epstein-Barr virus (EBV) not only causes infectious mononucleosis (glandular fever), but is also associated with cancers such as Hodgkin's lymphoma and Burkitt's lymphoma.
Efforts are made to develop drugs that target viral proteins but those efforts have not been wholly successful. For example, where a virus is in a latent state, not actively expressing its proteins, there is nothing to target. Additionally, any effort to eradicate a viral infection is not useful if it interferes with host cellular function. For example, an enzyme that prevents viral replication is not helpful if it interferes with genome replication in cells throughout the host.